You may need to specify your question a little more. Is there a specifc body part you are asking about? If not, then consider how any organism works. Each part of the body works in concert with another part. Therefore, the entire body works together. The heart pumps blood through your body, bringing vital oxygen and nutrients to major organs.
Take a look at the metabolic function called the "citric acid cylcle," or "Krebs Cycle" at the link below.
It is a simplified view of how the metabolism works but also is a smaller representation of how your entire body works: in harmony.
Unfortunately, because each body function and organ is so intertwined with another, diseases like cancer can spread rapidly through the body as well.
well one example will be the respiratory system providing oxygen to the circulatory system which then passed it around in the body.